Diffusion of In and Ga in selenized Cu-In and Cu-Ga precursors

Abstract

The interdiffusion of Ga and In in a CuGaSe/sub 2//CuInSe/sub 2/ thin film diffusion couple and the diffusion of In into CuGaSe/sub 2/ thin films were studied by Auger depth profiling. CuGaSe/sub 2/ and CuInSe/sub 2/ were obtained via selenization by H/sub 2/Se of sequentially deposited Cu-Ga and Cu-In layers, respectively. The CuGaSe/sub 2//CuInSe/sub 2/ diffusion couple was annealed at 650/spl deg/C for 30 minutes in an argon atmosphere. The thin film source of In was diffused into CuGaSe/sub 2/ in the temperature range of 400/spl deg/C to 600/spl deg/C for 30 minutes in an argon atmosphere. Bulk interdiffusion coefficients of In and Ga in the CuGaSe/sub 2//GuInSe/sub 2/ couple annealed at 650/spl deg/C, and the diffusion coefficients of In in CuGaSe/sub 2/ films diffusion annealed at various temperatures were determined. The interdiffusion coefficients of In and Ga at 650/spl deg/C in the diffusion couple are similar (D/sub In/=1.5/spl times/10/sup -11/ cm/sup 2//sec and D/sub Ga/=4.0/spl times/10/sup -11/ cm/sup 2//sec). The diffusion coefficients of In in CuGaSe/sub 2/ thin films varied from 2.0/spl times/10/sup -13/ cm/sup 2//sec to 4.5/spl times/10/sup -12/ cm/sup 2//sec in the temperature range of 400/spl deg/C to 600/spl deg/C.